The present invention relates to a leak detector for lumened instruments. It finds particular application as a leak detector for endoscopes of the watertight type. It will be appreciated, however, that the invention is also applicable to the detection of leaks in other lumened devices.
Endoscopes and other lumened medical instruments are typically subjected to a thorough cleaning and antimicrobial decontamination between each use. During endoscopic procedures, the devices become coated with blood and other protein-rich body fluids. The endoscopes have a watertight structure in which elements that are sensitive to water, detergents, and antimicrobial agents are contained so that it is possible to wash and sterilize the whole body of the endoscope by immersion or spraying in a washing liquid and an antiseptic solution. However, when there are defects in the watertight structure of the sensitive elements, or pinholes and cracks in a sheath of the endoscope""s flexible tube, washing and antiseptic solutions can leak into the inside of the water tight portions of the endoscope. This may lead to corrosion of the operating devices, or leakage of the solutions into the bundle of optical fibers, resulting in hindrance of transmission of light. In addition, patients could be harmed if trapped washing or antiseptic liquids later leak from the inside of the endoscope while in use.
To minimize these problems, methods have been developed to detect for leaks in an endoscope. In a conventional leak test procedure, a source of compressed air is attached to the endoscope. The source exhaust port is closed and the endoscope pressurized until a pressure gauge registers that the pressure within it is within a predetermined xe2x80x9cpressure holdxe2x80x9d range (typically 1140 to 220 mm of mercury). An observation is made to verify that the scope holds this pressure without falling outside the range. Falling outside this range would indicate a gross leak. The endoscope is then totally submerged in a tub of warm water. If the pressure drops, the endoscope is considered leaky and the test discontinued. If the pressure is maintained in the pressure hold range, the operator is instructed to articulate the control handle knobs of the endoscope to flex the distal tip of the endoscope, and visually inspect the device for bubble generation. An inability to maintain pressure during the pressure hold phase, or the generation of a single bubble in a period of one to two minutes is considered to be an endoscope failure. The operator is instructed to discontinue endoscope reprocessing until the device has been inspected and repaired.
The manual leak check procedure is prone to human error, especially with the increasing demand for rapid reprocessing and turnaround of endoscope devices. For example, bubbles may not become evident until two to three minutes into the pressure hold phase. This is well beyond the one to two minutes time frame allotted for the typical leak check. Another problem with the manual leak check procedure is the potential for the operator to leave the endoscope pressurized during subsequent reprocessing. If this occurs, the distal tip will inflate, as the internal pressure increases in the elevated temperature of the processing solution (typically about 50xc2x0 C.). This can lead to extensive endoscope damage and costly repairs.
Some automated reprocessing systems include a leak check step prior to disinfection of the endoscope. However, changes in ambient temperature can lead to increases in the internal pressure within the endoscope and lead to erroneous assessments. The reprocessing vessel is frequently warm from a prior reprocessing procedure and the internal temperature of the endoscope often rises, as a result, during the leak check.
The present invention provides a new and improved leak detector and method of use, which overcomes the above-referenced problems and others.
In accordance with one aspect of the present invention, a leak detection system for evaluating the integrity of a device with an internal passage is provided. The system includes an interior chamber. A connector is adapted for releasably connecting the interior chamber with the internal passage of the device. A source of a compressed gas is fluidly connected with the interior chamber and supplies the interior chamber and the internal passage with gas. A pressure sensor and a temperature sensor in communication with the interior chamber detect pressure and temperature within the interior chamber. A valve selectively seals the interior chamber and the internal passage from the source of compressed gas.
In accordance with another aspect of the present invention, a method for detecting the integrity of a device with an internal passage is provided. The method includes supplying a quantity of gas under pressure to the internal passage of the device and measuring a temperature and a pressure of the gas within the internal passage at a first time. The method further includes holding the quantity of gas within the internal passage and measuring the temperature of the gas within the internal passage at a second time. The method further includes determining a function of the temperature and the pressure of the gas within the internal passage at the first and second times, the function indicating whether leakage of the gas from the internal passage has occurred.
In accordance with another aspect of the present invention, a system for reprocessing a device with an internal passage is provided. The system includes a vessel for receiving the device and a source of a liquid microbial decontaminant connected with the chamber, which supplies the decontaminant to the chamber for microbially decontaminating the device. A leak detection system is provided for evaluating the integrity of the internal passage. The leak detection system includes a source of compressed gas selectively connectable with the internal passage, which supplies the internal passage with gas, a pressure sensor and a temperature sensor, in communication with the internal passage, which detect pressure and temperature within the internal passage, and a valve, which selectively seals the internal passage from the source of compressed gas.
In accordance with another aspect of the present invention, a method of reprocessing endoscopes is provided. The method includes positioning an endoscope in a vessel, connecting a leak detector to the endoscope, and supplying a quantity of compressed gas to an internal passage of the endoscope to pressurize the internal passage. The method further includes determining whether the endoscope has leaks from changes in the temperature and pressure of the gas with time, and in the event that the endoscope is determined not to have leaks, supplying a decontamination solution to the vessel to contact and decontaminate the endoscope.
One advantage of the present invention resides in rapid detection of leaks in an endoscope. Another advantage of the present invention resides in its compensation for variations in ambient temperature.
Yet another advantage of the present invention is that it minimizes the potential for operator errors.
Still further advantages and benefits of the present invention will become apparent to those of ordinary skill in the art upon reading and understanding the following detailed description of the preferred embodiments.